AB-INITIO QUASI-PARTICLE ENERGIES IN 2H, 4H, AND 6H SIC

Ab initio quasiparticle energies are calculated for the 2H, 4H, and 6H polytypes of SiC within the GW approximation for the self-energy. The starting point is a calculation within the pseudopotential local-dens ity approximation framework. The calculated fundamental gaps of 3.15, 3.35, and 3.24 eV for 2H, 4H, and 6H SiC, respectively, show very good agreement with experimental data. The energy dependence of the screen ed interaction is modeled by a plasmon pole model from which the plasm on band structures are obtained.